The invention concerns a hydraulically setting shaped brick, particularly for construction, and a method for its production.
Shaped brick of the above mentioned type is used in the construction industry in great amounts, on the one hand in the form of sand-lime brick, and, on the other hand, in the form of cement brick, with which the mineral flux material (so-called aggregate) is composed of sand. Herewith by shaped bricks is to be understood, that the starting material is poured into pre-fabricated and/or specified molds, and then subsequently hardened inside or outside (after its removal) of the mold. In contrast to the shaped bricks burned from loam or clay, cement bricks have the advantage that their production is less expensive and requires less energy, sand-lime brick displaying beyond that particularly high strength. On account of decade-long great demand, the raw material basis for many sand-lime brick and cement brick producers has considerably decreased through the exhaustion of particular deposits, so that the customary raw material (sand) must be transported over great distances.
With the method according to German Patent DE-PS No. 26 39 178, instead of sand, a broken slag granulation, in particular granulated blast furnace slag, is used as aggregate material together with lime as binding agent for the production of lime granulate bricks, which in their characteristics correspond to or approach the customary lime-sand bricks.
Therewith the aggregate material is produced in such manner that the slag is ground through crushing, so that the finest grain portion of the granulate, below 0.2 mm, amounts to 15 to 50% by weight. As binding agent, lime is used in a portion from 1 to 6% of the total weight, calculated as CaO.
From German Offenlegungsschrift DE-OS No. 25 22 851 it is known to form a hydraulically setting construction material for roadbuilding, its mineral grain mixture composed completely or predominantly of washed mining waste material from coal mining, which is solidified and cement-stabilized with 4 to 15% by weight cement or lime as binding agent; herewith the washed mining waste material is used without pretreatment.
In mining, above all in coal and particularly in hard coal mining--but also in ore mining--considerable amounts of country rock (mining waste material) appear in the crude, raw ore, whereby the portion of this mining waste material amounts to about 45% of the raw output, e.g. in hard coal mining. Through multiple-stage working up, the mining waste material is separated from the coal or the ore, and then by far predominantly deposited. Efforts towards a further use of the material have indeed so far led to a considerable reduction of the amounts deposited; nevertheless, still always the preponderant amount of waste material must be deposited. The difficulties with the yield and use are based on, among others, the instability, the inhomogeneity, and the content of burnable components of this material. A portion of the mining waste material produced is often brought to the surface already separated. Often, this mining waste material is brought to the surface together with the raw coal or the raw ore, and led to the appropriate working-up plants; they are then components of the so-called treatment tailings, in particular the washed mining waste material.